This invention relates to a safety apparatus for a room heating device for preventing an accident because of lack of oxygen at a burner at the time of room heating.
Incomplete combustion of gas in a burner caused by a low oxygen concentration in the combustion air can result in contamination of the air with carbon monoxide in a room during a room heating operation. In this view, there has been hitherto proposed a certain safety apparatus utilizing the incomplete combustion of a burner as a barometer of the degree of contamination of the air in the room. The incomplete combustion is detected by a combustion detecting element. When a detecting output thereof is changed to a predetermined operation level, the gas supply to the burner is cut off to prevent an oxygen deficiency accident. However, the state of contamination of air in the room during room heating is such that the degree of contamination of air is higher at an upper position in the room by the drafting of combustion exhaust gas. Accordingly, in the case of using a floor-type heating device installed on a floor, when the oxygen concentration in air supplied from the lower portion of the interior of the room is so lowered as to cause incomplete combustion of the burner, there is a danger of contamination of the air at the upper portion of the room going beyond an allowable value. In this case, if there is provided a room air-circulation fan inside or outside the heating device so that air in the room may be circulated forcibly, there is no difference in upper and lower air contamination degrees and the above danger is removed. However, in some cases, some of the users do not like a warm wind blowing against them, and therefore it is desirable to secure safety regardless of operation and non-operation of the circulation fan.